The present invention concerns a means for feeding a tree trunk into a machine processing round timber, with centering of the trunk in the lateral and vertical directions.
When feeding a log into round timber processing machines of certain types, e.g. hewing machines, hewing saws or butt end trimmers, one has to be able to supply or feed, the log to the processing cutters or blades, in a way ensuring that it is centered in lateral and vertical direction in accordance with said processing cutters' center-line (e.g., Finnish patent application No. 792067). In addition, the log must, before it is fed in between the processing cutters or blades, be rotated into proper position in view of its crookedness, for instance with the convex side downwards. Rotating a crooked log has heretofore been done manually or mechanically with complicated structures in which, for instance, rotation of the log being fed is accomplished with two pairs of chains in which the chains are placed at a V-angle with reference to each other. Pairs of wheels have also been used heretofore, the log being turned into correct position by accordingly rotating these wheels. One way is to feed the log through between opposed wheels rotatable about axles which are longitudinal as seen in the direction of the log, turning being accomplished by adjusting the axial lines of the wheels with reference to each other. Furthermore, it has been possible to guide the log through between vertical, spring-loaded roller sets, thus forcing the log at it passes through between the rollers into proper feeding position in view of its crookedness.
The problem in the rotating methods mentioned above is, however, undoubtedly the fact that they fail to center the log both in the vertical and in the lateral direction and that the feeding machines have a complex design, being therefore expensive and requiring much maintenance work.